Scarifier tooth



C. M. WALKER SCARIFIER TOOTH July 10, 1934.

Filed Nov. ,7, 1932 l NVENTO/R Carroll M Ifl" BY 4340 ATTOR N EY Patented July 10, 1934 UNITED STATES PATENT OFFICE Mills Alloys, Ine., poratlon of Delaware Los' Angeles, Calif., a cor- Applicafion November 7, .1932, Serial No. 641,584

7 Claims. (01. 262-33) This invention relates to scarifler teeth. Such teeth in general usually comprise 9. narrow body with an advancing or leading edge, for

engagement with the earth's surface, for scarifying or loosening it. Since considerable friction is developed between the active portion of the teeth and the earth through which it is drawn, these teeth are subjected to considerable wear.

It has been proposed to reduce'the extent of the f (scale, taken along plane 3-3 of Fig. 2; and

10 wear, and thereby to lengthen the life of the teeth,

b the addition of a hard facing compound inte y edge of the tooth.

grally fused to the leading edge of the tooth. Such a compound, for example, may be tungsten carb ody 1 of appropriate length andof general recbide particles in an iron or other-metallic matrix or. binder, which compound is integrally fused to the body of the tooth, as by Welling.

It is one of the objects of this invention to improve in general, scariner toeth 'of this, character; and especially by ensurlngmgaihst sterious effects of shocks imparted to the leading edge of the tube. g

More specifically, if athick layer of such atungstencarbide-compound be applied to the leading edge, this thick layer, even. if it be embedded in a groove along the leading edge, has brittle characteristics; and shocks imparted to the tooth by being dragged through the material to be scarifled may readily crack or break the layer of compound. This may occur in spite-of the factthat an. integral fusionhas taken place between the compound and the body of the tooth.

This disadvantage is obviated by the aid of the present invention. By building up the hard wearing edge inlaminations or layers altematingwith layers of metal having good shock resisting characteristics, the shocks to which the toothmay be exposed are quite evenly distributed throughout these alternate layers, and they can withstand the blows and shocks without material danger of breaking or cracking.

It is still another object of this invention to make it'possible to control the maximum bluntnessof the tooth; more specifically, by reducing the depth of .the active portion of the tooth; ,as

well as the area thereof, as by the aid of a deep groove in the back of the tooth.

My invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of one embodiment of my invention. For this purpose I have shown a form in the drawing accompanying and forming part of the present specification. I shall now proceed to describe this form in detail, which illustrates the general principles of my 56 invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of my invention is best defined by the appended claims.

Referring to the drawing: v Figure 1 is a side elevation of a scarifier tooth embodying the invention, but partly broken away in order to reduce the size of the figure;

A Fig. 2 is a front elevation thereof;

Fig. 3 is a crosssectional view on an enlarged Fig. 4 is an enlarged detail section through the The tooth in general can have a longitudinal tangular configuration. The lower edge of the 7 body 1 is shown as tapered as at 2, to provide a, pointed leading edge 5. Furthermore, the active portion of the tooth is cut away to a plane 3 to reduce the area of the cutting point, a deep groove 4 is provided'in the back thereof. The

leading face of the tooth is preferably sharply beveled, as shown, to assist in the scarifying action.

Preferably, the body ismade from shock resisting metal. Such metal may be mild steel or chrome, vanadium steel, or the like. It is apparent that as the tip 5 wears, the maximum area of contact between the worn tip and the ground is governed by the area of the cross section of the tooth. This area is reduced by the slot 4, as well as by cutting the back of the tooth away to the plane 3. Accordingly, the tooth remains sufliciently sharp to be continued in service until it wears down to the unreduced section of the body 1.

Preferably, the leading edge of the tooth is overlaid with hard wearing material. To accommodate the hard wearing material, a groove 6 extending longitudinally of the leading edge can be provided in the tooth.- Ihis groove is pref- 9 I erably formed with a round or substantially round bottom. This groove can be appropriately formed by a machining operation, but other ways for providing the groove can be utilized.

The hard facing material fills the groove and extends over substantially the entire area of the leading edge of the. tooth. One of the most desirable forms of hard wearing material is a compound of tungsten carbide granules and a binder of iron, iron alloy, nickel, cobalt, or other 1 5 metals of the iron group. Although a wide range in size -in tungsten carbide granules can be utilized, they are usually of the order of granules that will stay on a 30 mesh screen and that will pass through a 16 mesh screen.

The mechanical mixture or compound of tungsten carbide granules and the binder material is deposited in groove 6 in alternate layers 7, 8. 9, 10, and ll. Alternating between these layers are layers of metal l2, 13, 14 and 15 having shock resisting characteristics, and preferably of the same material as the body 1. Such material may be mild steel or some other iron alloy.

These alternate layers 7 to 15 inclusive are deposited in succession, preferably by a welding action, such as by the aid of an oxy-acetylene torch. The binder of the compound is fused by the torch, but the tungsten carbide particles are not affected thereby. Therefore, the binder holds the granules firmly in place, and is integrally fused to the tooth. It has been found that a sufficient amount of binder material is secured when using 10 percent or more by weight of the total compound for the binder material.

After the first layer 7 is thus deposited, the shock resisting layer 12 can be deposited thereover by an ordinary welding operation; and succeeding layers are formed in alternation as just described.

The outermost layer 11 can be extended as indicated in Fig. 3 to' cover substantially the entire leading edge of the tooth. It is also apparent that the alternate layers of hard wearing and shock resisting materials provide a structure that can withstand long wear and hard usage. In general practice, the groove 6 can be of the order of onehalf inch wide and about one-half inch deep. The layers of hard wearing material, such as '7, 8, 9, 10 and 11 can be of the order of one-sixteenth of an inch thick; and the alternate layers 12, 13, 14 and 15 of shock resisting material can be made thinner.

I claim:

1. A scarifier tooth having a metal body, with a leading edge, and alternate layers of hard wearing material and metal of the same general char acteristic as the body metal, said layers being integrally fused to the leading edge, and spaced in the direction of travel of the edge.

2. A scarifier tooth having a metal body, with a leading edge, and alternate layers of a compound of hard particles and a metallic binder, and of shock resisting metal, said layers being integrally fused to the leading edge, and spaced in the direction of travel of the edge..-

3. A scarifier tooth made from metal and having a longitudinal groove along its leading edge, and alternate layers of hard wearing material and shock resisting metal in said groove and integrally fused to the tooth, said layers being substantially coextensive with the groove and extending lengthwise thereof.

4. A scarifier tooth made from metal and having a longitudinal groove along its leading edge, and alternate layers of a compound of hard particles and a metallic binder, and of shock resisting metal in said groove and integrally fused to the tooth, said layers being substantially coextensive with the groove and extending lengthwise thereof.

5. A scarifier tooth having a metal body, with a leading edge, and alternate layers of a compound of tungsten carbide particles and a metallic binder, and of shock resisting metal, said layers being integrally fused to the leading edge, and spaced in the direction of travel of the edge.

6. A scarifier tooth made from metal and having a longitudinal groove along its leading edge, and alternate layers of a compound of tungsten carbide particles and a metallic binder, and of shock resisting metal in said groove and integrally fused to the tooth, and spaced in the direction of travel of the edge.

'7. A scarifier tooth made from metal and having a longitudinal groove along its leading edge, alternate layers of hard wearing material and a softer metal in said groove and integrally fused to the tooth, said layers being substantially coextensive with the groove and extending lengthwise thereof, and a supplemental layer of hard wearing material disposed over the groove and adjacent the edges thereof.

CARROLL M. WALKER. 

